Test is_default for share type and share group type

The share type and share group type APIs in version 2.46
returns is_default key, this patch is to test this featue.

Depends-On: https://review.openstack.org/#/c/557206/
Change-Id: I68f7bea991fb39c4667031b0125470936a28dc9f
Partial-Bug: #1743941
diff --git a/manila_tempest_tests/config.py b/manila_tempest_tests/config.py
index 0517c60..c24a50e 100644
--- a/manila_tempest_tests/config.py
+++ b/manila_tempest_tests/config.py
@@ -30,7 +30,7 @@
                help="The minimum api microversion is configured to be the "
                     "value of the minimum microversion supported by Manila."),
     cfg.StrOpt("max_api_microversion",
-               default="2.45",
+               default="2.46",
                help="The maximum api microversion is configured to be the "
                     "value of the latest microversion supported by Manila."),
     cfg.StrOpt("region",